package com.cloudcc.cloudframe.util;

import java.lang.reflect.Array;
import java.math.BigDecimal;
import java.math.BigInteger;

/**
 * <p>
 * Provides extra functionality for Java Number classes.
 * </p>
 * 
 * @since 2.0
 * @version $Id: NumberUtils.java 1582585 2014-03-28 03:10:27Z niallp $
 */
public class NumberUtils {

	/** Reusable Long constant for zero. */
	public static final Long LONG_ZERO = Long.valueOf(0L);
	/** Reusable Long constant for one. */
	public static final Long LONG_ONE = Long.valueOf(1L);
	/** Reusable Long constant for minus one. */
	public static final Long LONG_MINUS_ONE = Long.valueOf(-1L);
	/** Reusable Integer constant for zero. */
	public static final Integer INTEGER_ZERO = Integer.valueOf(0);
	/** Reusable Integer constant for one. */
	public static final Integer INTEGER_ONE = Integer.valueOf(1);
	/** Reusable Integer constant for minus one. */
	public static final Integer INTEGER_MINUS_ONE = Integer.valueOf(-1);
	/** Reusable Short constant for zero. */
	public static final Short SHORT_ZERO = Short.valueOf((short) 0);
	/** Reusable Short constant for one. */
	public static final Short SHORT_ONE = Short.valueOf((short) 1);
	/** Reusable Short constant for minus one. */
	public static final Short SHORT_MINUS_ONE = Short.valueOf((short) -1);
	/** Reusable Byte constant for zero. */
	public static final Byte BYTE_ZERO = Byte.valueOf((byte) 0);
	/** Reusable Byte constant for one. */
	public static final Byte BYTE_ONE = Byte.valueOf((byte) 1);
	/** Reusable Byte constant for minus one. */
	public static final Byte BYTE_MINUS_ONE = Byte.valueOf((byte) -1);
	/** Reusable Double constant for zero. */
	public static final Double DOUBLE_ZERO = Double.valueOf(0.0d);
	/** Reusable Double constant for one. */
	public static final Double DOUBLE_ONE = Double.valueOf(1.0d);
	/** Reusable Double constant for minus one. */
	public static final Double DOUBLE_MINUS_ONE = Double.valueOf(-1.0d);
	/** Reusable Float constant for zero. */
	public static final Float FLOAT_ZERO = Float.valueOf(0.0f);
	/** Reusable Float constant for one. */
	public static final Float FLOAT_ONE = Float.valueOf(1.0f);
	/** Reusable Float constant for minus one. */
	public static final Float FLOAT_MINUS_ONE = Float.valueOf(-1.0f);

	/**
	 * <p>
	 * <code>NumberUtils</code> instances should NOT be constructed in standard
	 * programming. Instead, the class should be used as
	 * <code>NumberUtils.toInt("6");</code>.
	 * </p>
	 * 
	 * <p>
	 * This constructor is public to permit tools that require a JavaBean
	 * instance to operate.
	 * </p>
	 */
	public NumberUtils() {
		super();
	}

	// -----------------------------------------------------------------------
	/**
	 * <p>
	 * Convert a <code>String</code> to an <code>int</code>, returning
	 * <code>zero</code> if the conversion fails.
	 * </p>
	 * 
	 * <p>
	 * If the string is <code>null</code>, <code>zero</code> is returned.
	 * </p>
	 * 
	 * <pre>
	 *   NumberUtils.toInt(null) = 0
	 *   NumberUtils.toInt("")   = 0
	 *   NumberUtils.toInt("1")  = 1
	 * </pre>
	 * 
	 * @param str
	 *            the string to convert, may be null
	 * @return the int represented by the string, or <code>zero</code> if
	 *         conversion fails
	 * @since 2.1
	 */
	public static int toInt(final String str) {
		return toInt(str, 0);
	}

	/**
	 * <p>
	 * Convert a <code>String</code> to an <code>int</code>, returning a default
	 * value if the conversion fails.
	 * </p>
	 * 
	 * <p>
	 * If the string is <code>null</code>, the default value is returned.
	 * </p>
	 * 
	 * <pre>
	 *   NumberUtils.toInt(null, 1) = 1
	 *   NumberUtils.toInt("", 1)   = 1
	 *   NumberUtils.toInt("1", 0)  = 1
	 * </pre>
	 * 
	 * @param str
	 *            the string to convert, may be null
	 * @param defaultValue
	 *            the default value
	 * @return the int represented by the string, or the default if conversion
	 *         fails
	 * @since 2.1
	 */
	public static int toInt(final String str, final int defaultValue) {
		if (str == null) {
			return defaultValue;
		}
		try {
			return Integer.parseInt(str);
		} catch (final NumberFormatException nfe) {
			return defaultValue;
		}
	}

	/**
	 * <p>
	 * Convert a <code>String</code> to a <code>long</code>, returning
	 * <code>zero</code> if the conversion fails.
	 * </p>
	 * 
	 * <p>
	 * If the string is <code>null</code>, <code>zero</code> is returned.
	 * </p>
	 * 
	 * <pre>
	 *   NumberUtils.toLong(null) = 0L
	 *   NumberUtils.toLong("")   = 0L
	 *   NumberUtils.toLong("1")  = 1L
	 * </pre>
	 * 
	 * @param str
	 *            the string to convert, may be null
	 * @return the long represented by the string, or <code>0</code> if
	 *         conversion fails
	 * @since 2.1
	 */
	public static long toLong(final String str) {
		return toLong(str, 0L);
	}

	/**
	 * <p>
	 * Convert a <code>String</code> to a <code>long</code>, returning a default
	 * value if the conversion fails.
	 * </p>
	 * 
	 * <p>
	 * If the string is <code>null</code>, the default value is returned.
	 * </p>
	 * 
	 * <pre>
	 *   NumberUtils.toLong(null, 1L) = 1L
	 *   NumberUtils.toLong("", 1L)   = 1L
	 *   NumberUtils.toLong("1", 0L)  = 1L
	 * </pre>
	 * 
	 * @param str
	 *            the string to convert, may be null
	 * @param defaultValue
	 *            the default value
	 * @return the long represented by the string, or the default if conversion
	 *         fails
	 * @since 2.1
	 */
	public static long toLong(final String str, final long defaultValue) {
		if (str == null) {
			return defaultValue;
		}
		try {
			return Long.parseLong(str);
		} catch (final NumberFormatException nfe) {
			return defaultValue;
		}
	}

	/**
	 * <p>
	 * Convert a <code>String</code> to a <code>float</code>, returning
	 * <code>0.0f</code> if the conversion fails.
	 * </p>
	 * 
	 * <p>
	 * If the string <code>str</code> is <code>null</code>, <code>0.0f</code> is
	 * returned.
	 * </p>
	 * 
	 * <pre>
	 *   NumberUtils.toFloat(null)   = 0.0f
	 *   NumberUtils.toFloat("")     = 0.0f
	 *   NumberUtils.toFloat("1.5")  = 1.5f
	 * </pre>
	 * 
	 * @param str
	 *            the string to convert, may be <code>null</code>
	 * @return the float represented by the string, or <code>0.0f</code> if
	 *         conversion fails
	 * @since 2.1
	 */
	public static float toFloat(final String str) {
		return toFloat(str, 0.0f);
	}

	/**
	 * <p>
	 * Convert a <code>String</code> to a <code>float</code>, returning a
	 * default value if the conversion fails.
	 * </p>
	 * 
	 * <p>
	 * If the string <code>str</code> is <code>null</code>, the default value is
	 * returned.
	 * </p>
	 * 
	 * <pre>
	 *   NumberUtils.toFloat(null, 1.1f)   = 1.0f
	 *   NumberUtils.toFloat("", 1.1f)     = 1.1f
	 *   NumberUtils.toFloat("1.5", 0.0f)  = 1.5f
	 * </pre>
	 * 
	 * @param str
	 *            the string to convert, may be <code>null</code>
	 * @param defaultValue
	 *            the default value
	 * @return the float represented by the string, or defaultValue if
	 *         conversion fails
	 * @since 2.1
	 */
	public static float toFloat(final String str, final float defaultValue) {
		if (str == null) {
			return defaultValue;
		}
		try {
			return Float.parseFloat(str);
		} catch (final NumberFormatException nfe) {
			return defaultValue;
		}
	}

	/**
	 * <p>
	 * Convert a <code>String</code> to a <code>double</code>, returning
	 * <code>0.0d</code> if the conversion fails.
	 * </p>
	 * 
	 * <p>
	 * If the string <code>str</code> is <code>null</code>, <code>0.0d</code> is
	 * returned.
	 * </p>
	 * 
	 * <pre>
	 *   NumberUtils.toDouble(null)   = 0.0d
	 *   NumberUtils.toDouble("")     = 0.0d
	 *   NumberUtils.toDouble("1.5")  = 1.5d
	 * </pre>
	 * 
	 * @param str
	 *            the string to convert, may be <code>null</code>
	 * @return the double represented by the string, or <code>0.0d</code> if
	 *         conversion fails
	 * @since 2.1
	 */
	public static double toDouble(final String str) {
		return toDouble(str, 0.0d);
	}

	/**
	 * <p>
	 * Convert a <code>String</code> to a <code>double</code>, returning a
	 * default value if the conversion fails.
	 * </p>
	 * 
	 * <p>
	 * If the string <code>str</code> is <code>null</code>, the default value is
	 * returned.
	 * </p>
	 * 
	 * <pre>
	 *   NumberUtils.toDouble(null, 1.1d)   = 1.1d
	 *   NumberUtils.toDouble("", 1.1d)     = 1.1d
	 *   NumberUtils.toDouble("1.5", 0.0d)  = 1.5d
	 * </pre>
	 * 
	 * @param str
	 *            the string to convert, may be <code>null</code>
	 * @param defaultValue
	 *            the default value
	 * @return the double represented by the string, or defaultValue if
	 *         conversion fails
	 * @since 2.1
	 */
	public static double toDouble(final String str, final double defaultValue) {
		if (str == null) {
			return defaultValue;
		}
		try {
			return Double.parseDouble(str);
		} catch (final NumberFormatException nfe) {
			return defaultValue;
		}
	}

	// -----------------------------------------------------------------------
	/**
	 * <p>
	 * Convert a <code>String</code> to a <code>byte</code>, returning
	 * <code>zero</code> if the conversion fails.
	 * </p>
	 * 
	 * <p>
	 * If the string is <code>null</code>, <code>zero</code> is returned.
	 * </p>
	 * 
	 * <pre>
	 *   NumberUtils.toByte(null) = 0
	 *   NumberUtils.toByte("")   = 0
	 *   NumberUtils.toByte("1")  = 1
	 * </pre>
	 * 
	 * @param str
	 *            the string to convert, may be null
	 * @return the byte represented by the string, or <code>zero</code> if
	 *         conversion fails
	 * @since 2.5
	 */
	public static byte toByte(final String str) {
		return toByte(str, (byte) 0);
	}

	/**
	 * <p>
	 * Convert a <code>String</code> to a <code>byte</code>, returning a default
	 * value if the conversion fails.
	 * </p>
	 * 
	 * <p>
	 * If the string is <code>null</code>, the default value is returned.
	 * </p>
	 * 
	 * <pre>
	 *   NumberUtils.toByte(null, 1) = 1
	 *   NumberUtils.toByte("", 1)   = 1
	 *   NumberUtils.toByte("1", 0)  = 1
	 * </pre>
	 * 
	 * @param str
	 *            the string to convert, may be null
	 * @param defaultValue
	 *            the default value
	 * @return the byte represented by the string, or the default if conversion
	 *         fails
	 * @since 2.5
	 */
	public static byte toByte(final String str, final byte defaultValue) {
		if (str == null) {
			return defaultValue;
		}
		try {
			return Byte.parseByte(str);
		} catch (final NumberFormatException nfe) {
			return defaultValue;
		}
	}

	/**
	 * <p>
	 * Convert a <code>String</code> to a <code>short</code>, returning
	 * <code>zero</code> if the conversion fails.
	 * </p>
	 * 
	 * <p>
	 * If the string is <code>null</code>, <code>zero</code> is returned.
	 * </p>
	 * 
	 * <pre>
	 *   NumberUtils.toShort(null) = 0
	 *   NumberUtils.toShort("")   = 0
	 *   NumberUtils.toShort("1")  = 1
	 * </pre>
	 * 
	 * @param str
	 *            the string to convert, may be null
	 * @return the short represented by the string, or <code>zero</code> if
	 *         conversion fails
	 * @since 2.5
	 */
	public static short toShort(final String str) {
		return toShort(str, (short) 0);
	}

	/**
	 * <p>
	 * Convert a <code>String</code> to an <code>short</code>, returning a
	 * default value if the conversion fails.
	 * </p>
	 * 
	 * <p>
	 * If the string is <code>null</code>, the default value is returned.
	 * </p>
	 * 
	 * <pre>
	 *   NumberUtils.toShort(null, 1) = 1
	 *   NumberUtils.toShort("", 1)   = 1
	 *   NumberUtils.toShort("1", 0)  = 1
	 * </pre>
	 * 
	 * @param str
	 *            the string to convert, may be null
	 * @param defaultValue
	 *            the default value
	 * @return the short represented by the string, or the default if conversion
	 *         fails
	 * @since 2.5
	 */
	public static short toShort(final String str, final short defaultValue) {
		if (str == null) {
			return defaultValue;
		}
		try {
			return Short.parseShort(str);
		} catch (final NumberFormatException nfe) {
			return defaultValue;
		}
	}

	// -----------------------------------------------------------------------
	// must handle Long, Float, Integer, Float, Short,
	// BigDecimal, BigInteger and Byte
	// useful methods:
	// Byte.decode(String)
	// Byte.valueOf(String,int radix)
	// Byte.valueOf(String)
	// Double.valueOf(String)
	// Float.valueOf(String)
	// Float.valueOf(String)
	// Integer.valueOf(String,int radix)
	// Integer.valueOf(String)
	// Integer.decode(String)
	// Integer.getInteger(String)
	// Integer.getInteger(String,int val)
	// Integer.getInteger(String,Integer val)
	// Integer.valueOf(String)
	// Double.valueOf(String)
	// new Byte(String)
	// Long.valueOf(String)
	// Long.getLong(String)
	// Long.getLong(String,int)
	// Long.getLong(String,Integer)
	// Long.valueOf(String,int)
	// Long.valueOf(String)
	// Short.valueOf(String)
	// Short.decode(String)
	// Short.valueOf(String,int)
	// Short.valueOf(String)
	// new BigDecimal(String)
	// new BigInteger(String)
	// new BigInteger(String,int radix)
	// Possible inputs:
	// 45 45.5 45E7 4.5E7 Hex Oct Binary xxxF xxxD xxxf xxxd
	// plus minus everything. Prolly more. A lot are not separable.

	/**
	 * <p>
	 * Turns a string value into a java.lang.Number.
	 * </p>
	 * 
	 * <p>
	 * If the string starts with {@code 0x} or {@code -0x} (lower or upper case)
	 * or {@code #} or {@code -#}, it will be interpreted as a hexadecimal
	 * Integer - or Long, if the number of digits after the prefix is more than
	 * 8 - or BigInteger if there are more than 16 digits.
	 * </p>
	 * <p>
	 * Then, the value is examined for a type qualifier on the end, i.e. one of
	 * <code>'f','F','d','D','l','L'</code>. If it is found, it starts trying to
	 * create successively larger types from the type specified until one is
	 * found that can represent the value.
	 * </p>
	 * 
	 * <p>
	 * If a type specifier is not found, it will check for a decimal point and
	 * then try successively larger types from <code>Integer</code> to
	 * <code>BigInteger</code> and from <code>Float</code> to
	 * <code>BigDecimal</code>.
	 * </p>
	 * 
	 * <p>
	 * Integral values with a leading {@code 0} will be interpreted as octal;
	 * the returned number will be Integer, Long or BigDecimal as appropriate.
	 * </p>
	 * 
	 * <p>
	 * Returns <code>null</code> if the string is <code>null</code>.
	 * </p>
	 * 
	 * <p>
	 * This method does not trim the input string, i.e., strings with leading or
	 * trailing spaces will generate NumberFormatExceptions.
	 * </p>
	 * 
	 * @param str
	 *            String containing a number, may be null
	 * @return Number created from the string (or null if the input is null)
	 * @throws NumberFormatException
	 *             if the value cannot be converted
	 */
	public static Number createNumber(final String str)
			throws NumberFormatException {
		if (str == null) {
			return null;
		}
		if (StringUtils.isBlank(str)) {
			throw new NumberFormatException(
					"A blank string is not a valid number");
		}
		// Need to deal with all possible hex prefixes here
		final String[] hex_prefixes = { "0x", "0X", "-0x", "-0X", "#", "-#" };
		int pfxLen = 0;
		for (final String pfx : hex_prefixes) {
			if (str.startsWith(pfx)) {
				pfxLen += pfx.length();
				break;
			}
		}
		if (pfxLen > 0) { // we have a hex number
			char firstSigDigit = 0; // strip leading zeroes
			for (int i = pfxLen; i < str.length(); i++) {
				firstSigDigit = str.charAt(i);
				if (firstSigDigit == '0') { // count leading zeroes
					pfxLen++;
				} else {
					break;
				}
			}
			final int hexDigits = str.length() - pfxLen;
			if (hexDigits > 16 || (hexDigits == 16 && firstSigDigit > '7')) { // too
																				// many
																				// for
																				// Long
				return createBigInteger(str);
			}
			if (hexDigits > 8 || (hexDigits == 8 && firstSigDigit > '7')) { // too
																			// many
																			// for
																			// an
																			// int
				return createLong(str);
			}
			return createInteger(str);
		}
		final char lastChar = str.charAt(str.length() - 1);
		String mant;
		String dec;
		String exp;
		final int decPos = str.indexOf('.');
		final int expPos = str.indexOf('e') + str.indexOf('E') + 1; // assumes
																	// both not
																	// present
		// if both e and E are present, this is caught by the checks on expPos
		// (which prevent IOOBE)
		// and the parsing which will detect if e or E appear in a number due to
		// using the wrong offset

		int numDecimals = 0; // Check required precision (LANG-693)
		if (decPos > -1) { // there is a decimal point

			if (expPos > -1) { // there is an exponent
				if (expPos < decPos || expPos > str.length()) { // prevents
																// double
																// exponent
																// causing IOOBE
					throw new NumberFormatException(str
							+ " is not a valid number.");
				}
				dec = str.substring(decPos + 1, expPos);
			} else {
				dec = str.substring(decPos + 1);
			}
			mant = str.substring(0, decPos);
			numDecimals = dec.length(); // gets number of digits past the
										// decimal to ensure no loss of
										// precision for floating point numbers.
		} else {
			if (expPos > -1) {
				if (expPos > str.length()) { // prevents double exponent causing
												// IOOBE
					throw new NumberFormatException(str
							+ " is not a valid number.");
				}
				mant = str.substring(0, expPos);
			} else {
				mant = str;
			}
			dec = null;
		}
		if (!Character.isDigit(lastChar) && lastChar != '.') {
			if (expPos > -1 && expPos < str.length() - 1) {
				exp = str.substring(expPos + 1, str.length() - 1);
			} else {
				exp = null;
			}
			// Requesting a specific type..
			final String numeric = str.substring(0, str.length() - 1);
			final boolean allZeros = isAllZeros(mant) && isAllZeros(exp);
			switch (lastChar) {
			case 'l':
			case 'L':
				if (dec == null
						&& exp == null
						&& (numeric.charAt(0) == '-'
								&& isDigits(numeric.substring(1)) || isDigits(numeric))) {
					try {
						return createLong(numeric);
					} catch (final NumberFormatException nfe) { // NOPMD
						// Too big for a long
					}
					return createBigInteger(numeric);

				}
				throw new NumberFormatException(str + " is not a valid number.");
			case 'f':
			case 'F':
				try {
					final Float f = NumberUtils.createFloat(numeric);
					if (!(f.isInfinite() || (f.floatValue() == 0.0F && !allZeros))) {
						// If it's too big for a float or the float value = 0
						// and the string
						// has non-zeros in it, then float does not have the
						// precision we want
						return f;
					}

				} catch (final NumberFormatException nfe) { // NOPMD
					// ignore the bad number
				}
				//$FALL-THROUGH$
			case 'd':
			case 'D':
				try {
					final Double d = NumberUtils.createDouble(numeric);
					if (!(d.isInfinite() || (d.floatValue() == 0.0D && !allZeros))) {
						return d;
					}
				} catch (final NumberFormatException nfe) { // NOPMD
					// ignore the bad number
				}
				try {
					return createBigDecimal(numeric);
				} catch (final NumberFormatException e) { // NOPMD
					// ignore the bad number
				}
				//$FALL-THROUGH$
			default:
				throw new NumberFormatException(str + " is not a valid number.");

			}
		}
		// User doesn't have a preference on the return type, so let's start
		// small and go from there...
		if (expPos > -1 && expPos < str.length() - 1) {
			exp = str.substring(expPos + 1, str.length());
		} else {
			exp = null;
		}
		if (dec == null && exp == null) { // no decimal point and no exponent
			// Must be an Integer, Long, Biginteger
			try {
				return createInteger(str);
			} catch (final NumberFormatException nfe) { // NOPMD
				// ignore the bad number
			}
			try {
				return createLong(str);
			} catch (final NumberFormatException nfe) { // NOPMD
				// ignore the bad number
			}
			return createBigInteger(str);
		}

		// Must be a Float, Double, BigDecimal
		final boolean allZeros = isAllZeros(mant) && isAllZeros(exp);
		try {
			if (numDecimals <= 7) {// If number has 7 or fewer digits past the
									// decimal point then make it a float
				final Float f = createFloat(str);
				if (!(f.isInfinite() || (f.floatValue() == 0.0F && !allZeros))) {
					return f;
				}
			}
		} catch (final NumberFormatException nfe) { // NOPMD
			// ignore the bad number
		}
		try {
			if (numDecimals <= 16) {// If number has between 8 and 16 digits
									// past the decimal point then make it a
									// double
				final Double d = createDouble(str);
				if (!(d.isInfinite() || (d.doubleValue() == 0.0D && !allZeros))) {
					return d;
				}
			}
		} catch (final NumberFormatException nfe) { // NOPMD
			// ignore the bad number
		}

		return createBigDecimal(str);
	}

	/**
	 * <p>
	 * Utility method for {@link #createNumber(String)}.
	 * </p>
	 * 
	 * <p>
	 * Returns <code>true</code> if s is <code>null</code>.
	 * </p>
	 * 
	 * @param str
	 *            the String to check
	 * @return if it is all zeros or <code>null</code>
	 */
	private static boolean isAllZeros(final String str) {
		if (str == null) {
			return true;
		}
		for (int i = str.length() - 1; i >= 0; i--) {
			if (str.charAt(i) != '0') {
				return false;
			}
		}
		return str.length() > 0;
	}

	// -----------------------------------------------------------------------
	/**
	 * <p>
	 * Convert a <code>String</code> to a <code>Float</code>.
	 * </p>
	 * 
	 * <p>
	 * Returns <code>null</code> if the string is <code>null</code>.
	 * </p>
	 * 
	 * @param str
	 *            a <code>String</code> to convert, may be null
	 * @return converted <code>Float</code> (or null if the input is null)
	 * @throws NumberFormatException
	 *             if the value cannot be converted
	 */
	public static Float createFloat(final String str) {
		if (str == null) {
			return null;
		}
		return Float.valueOf(str);
	}

	/**
	 * <p>
	 * Convert a <code>String</code> to a <code>Double</code>.
	 * </p>
	 * 
	 * <p>
	 * Returns <code>null</code> if the string is <code>null</code>.
	 * </p>
	 * 
	 * @param str
	 *            a <code>String</code> to convert, may be null
	 * @return converted <code>Double</code> (or null if the input is null)
	 * @throws NumberFormatException
	 *             if the value cannot be converted
	 */
	public static Double createDouble(final String str) {
		if (str == null) {
			return null;
		}
		return Double.valueOf(str);
	}

	/**
	 * <p>
	 * Convert a <code>String</code> to a <code>Integer</code>, handling hex
	 * (0xhhhh) and octal (0dddd) notations. N.B. a leading zero means octal;
	 * spaces are not trimmed.
	 * </p>
	 * 
	 * <p>
	 * Returns <code>null</code> if the string is <code>null</code>.
	 * </p>
	 * 
	 * @param str
	 *            a <code>String</code> to convert, may be null
	 * @return converted <code>Integer</code> (or null if the input is null)
	 * @throws NumberFormatException
	 *             if the value cannot be converted
	 */
	public static Integer createInteger(final String str) {
		if (str == null) {
			return null;
		}
		// decode() handles 0xAABD and 0777 (hex and octal) as well.
		return Integer.decode(str);
	}

	/**
	 * <p>
	 * Convert a <code>String</code> to a <code>Long</code>; since 3.1 it
	 * handles hex (0Xhhhh) and octal (0ddd) notations. N.B. a leading zero
	 * means octal; spaces are not trimmed.
	 * </p>
	 * 
	 * <p>
	 * Returns <code>null</code> if the string is <code>null</code>.
	 * </p>
	 * 
	 * @param str
	 *            a <code>String</code> to convert, may be null
	 * @return converted <code>Long</code> (or null if the input is null)
	 * @throws NumberFormatException
	 *             if the value cannot be converted
	 */
	public static Long createLong(final String str) {
		if (str == null) {
			return null;
		}
		return Long.decode(str);
	}

	/**
	 * <p>
	 * Convert a <code>String</code> to a <code>BigInteger</code>; since 3.2 it
	 * handles hex (0x or #) and octal (0) notations.
	 * </p>
	 * 
	 * <p>
	 * Returns <code>null</code> if the string is <code>null</code>.
	 * </p>
	 * 
	 * @param str
	 *            a <code>String</code> to convert, may be null
	 * @return converted <code>BigInteger</code> (or null if the input is null)
	 * @throws NumberFormatException
	 *             if the value cannot be converted
	 */
	public static BigInteger createBigInteger(final String str) {
		if (str == null) {
			return null;
		}
		int pos = 0; // offset within string
		int radix = 10;
		boolean negate = false; // need to negate later?
		if (str.startsWith("-")) {
			negate = true;
			pos = 1;
		}
		if (str.startsWith("0x", pos) || str.startsWith("0x", pos)) { // hex
			radix = 16;
			pos += 2;
		} else if (str.startsWith("#", pos)) { // alternative hex (allowed by
												// Long/Integer)
			radix = 16;
			pos++;
		} else if (str.startsWith("0", pos) && str.length() > pos + 1) { // octal;
																			// so
																			// long
																			// as
																			// there
																			// are
																			// additional
																			// digits
			radix = 8;
			pos++;
		} // default is to treat as decimal

		final BigInteger value = new BigInteger(str.substring(pos), radix);
		return negate ? value.negate() : value;
	}

	/**
	 * <p>
	 * Convert a <code>String</code> to a <code>BigDecimal</code>.
	 * </p>
	 * 
	 * <p>
	 * Returns <code>null</code> if the string is <code>null</code>.
	 * </p>
	 * 
	 * @param str
	 *            a <code>String</code> to convert, may be null
	 * @return converted <code>BigDecimal</code> (or null if the input is null)
	 * @throws NumberFormatException
	 *             if the value cannot be converted
	 */
	public static BigDecimal createBigDecimal(final String str) {
		if (str == null) {
			return null;
		}
		// handle JDK1.3.1 bug where "" throws IndexOutOfBoundsException
		if (StringUtils.isBlank(str)) {
			throw new NumberFormatException(
					"A blank string is not a valid number");
		}
		if (str.trim().startsWith("--")) {
			// this is protection for poorness in java.lang.BigDecimal.
			// it accepts this as a legal value, but it does not appear
			// to be in specification of class. OS X Java parses it to
			// a wrong value.
			throw new NumberFormatException(str + " is not a valid number.");
		}
		return new BigDecimal(str);
	}

	// Min in array
	// --------------------------------------------------------------------
	/**
	 * <p>
	 * Returns the minimum value in an array.
	 * </p>
	 * 
	 * @param array
	 *            an array, must not be null or empty
	 * @return the minimum value in the array
	 * @throws IllegalArgumentException
	 *             if <code>array</code> is <code>null</code>
	 * @throws IllegalArgumentException
	 *             if <code>array</code> is empty
	 */
	public static long min(final long[] array) {
		// Validates input
		validateArray(array);

		// Finds and returns min
		long min = array[0];
		for (int i = 1; i < array.length; i++) {
			if (array[i] < min) {
				min = array[i];
			}
		}

		return min;
	}

	/**
	 * <p>
	 * Returns the minimum value in an array.
	 * </p>
	 * 
	 * @param array
	 *            an array, must not be null or empty
	 * @return the minimum value in the array
	 * @throws IllegalArgumentException
	 *             if <code>array</code> is <code>null</code>
	 * @throws IllegalArgumentException
	 *             if <code>array</code> is empty
	 */
	public static int min(final int[] array) {
		// Validates input
		validateArray(array);

		// Finds and returns min
		int min = array[0];
		for (int j = 1; j < array.length; j++) {
			if (array[j] < min) {
				min = array[j];
			}
		}

		return min;
	}

	/**
	 * <p>
	 * Returns the minimum value in an array.
	 * </p>
	 * 
	 * @param array
	 *            an array, must not be null or empty
	 * @return the minimum value in the array
	 * @throws IllegalArgumentException
	 *             if <code>array</code> is <code>null</code>
	 * @throws IllegalArgumentException
	 *             if <code>array</code> is empty
	 */
	public static short min(final short[] array) {
		// Validates input
		validateArray(array);

		// Finds and returns min
		short min = array[0];
		for (int i = 1; i < array.length; i++) {
			if (array[i] < min) {
				min = array[i];
			}
		}

		return min;
	}

	/**
	 * <p>
	 * Returns the minimum value in an array.
	 * </p>
	 * 
	 * @param array
	 *            an array, must not be null or empty
	 * @return the minimum value in the array
	 * @throws IllegalArgumentException
	 *             if <code>array</code> is <code>null</code>
	 * @throws IllegalArgumentException
	 *             if <code>array</code> is empty
	 */
	public static byte min(final byte[] array) {
		// Validates input
		validateArray(array);

		// Finds and returns min
		byte min = array[0];
		for (int i = 1; i < array.length; i++) {
			if (array[i] < min) {
				min = array[i];
			}
		}

		return min;
	}

	/**
	 * <p>
	 * Returns the minimum value in an array.
	 * </p>
	 * 
	 * @param array
	 *            an array, must not be null or empty
	 * @return the minimum value in the array
	 * @throws IllegalArgumentException
	 *             if <code>array</code> is <code>null</code>
	 * @throws IllegalArgumentException
	 *             if <code>array</code> is empty
	 * @see IEEE754rUtils#min(double[]) IEEE754rUtils for a version of this
	 *      method that handles NaN differently
	 */
	public static double min(final double[] array) {
		// Validates input
		validateArray(array);

		// Finds and returns min
		double min = array[0];
		for (int i = 1; i < array.length; i++) {
			if (Double.isNaN(array[i])) {
				return Double.NaN;
			}
			if (array[i] < min) {
				min = array[i];
			}
		}

		return min;
	}

	/**
	 * <p>
	 * Returns the minimum value in an array.
	 * </p>
	 * 
	 * @param array
	 *            an array, must not be null or empty
	 * @return the minimum value in the array
	 * @throws IllegalArgumentException
	 *             if <code>array</code> is <code>null</code>
	 * @throws IllegalArgumentException
	 *             if <code>array</code> is empty
	 * @see IEEE754rUtils#min(float[]) IEEE754rUtils for a version of this
	 *      method that handles NaN differently
	 */
	public static float min(final float[] array) {
		// Validates input
		validateArray(array);

		// Finds and returns min
		float min = array[0];
		for (int i = 1; i < array.length; i++) {
			if (Float.isNaN(array[i])) {
				return Float.NaN;
			}
			if (array[i] < min) {
				min = array[i];
			}
		}

		return min;
	}

	// Max in array
	// --------------------------------------------------------------------
	/**
	 * <p>
	 * Returns the maximum value in an array.
	 * </p>
	 * 
	 * @param array
	 *            an array, must not be null or empty
	 * @return the minimum value in the array
	 * @throws IllegalArgumentException
	 *             if <code>array</code> is <code>null</code>
	 * @throws IllegalArgumentException
	 *             if <code>array</code> is empty
	 */
	public static long max(final long[] array) {
		// Validates input
		validateArray(array);

		// Finds and returns max
		long max = array[0];
		for (int j = 1; j < array.length; j++) {
			if (array[j] > max) {
				max = array[j];
			}
		}

		return max;
	}

	/**
	 * <p>
	 * Returns the maximum value in an array.
	 * </p>
	 * 
	 * @param array
	 *            an array, must not be null or empty
	 * @return the minimum value in the array
	 * @throws IllegalArgumentException
	 *             if <code>array</code> is <code>null</code>
	 * @throws IllegalArgumentException
	 *             if <code>array</code> is empty
	 */
	public static int max(final int[] array) {
		// Validates input
		validateArray(array);

		// Finds and returns max
		int max = array[0];
		for (int j = 1; j < array.length; j++) {
			if (array[j] > max) {
				max = array[j];
			}
		}

		return max;
	}

	/**
	 * <p>
	 * Returns the maximum value in an array.
	 * </p>
	 * 
	 * @param array
	 *            an array, must not be null or empty
	 * @return the minimum value in the array
	 * @throws IllegalArgumentException
	 *             if <code>array</code> is <code>null</code>
	 * @throws IllegalArgumentException
	 *             if <code>array</code> is empty
	 */
	public static short max(final short[] array) {
		// Validates input
		validateArray(array);

		// Finds and returns max
		short max = array[0];
		for (int i = 1; i < array.length; i++) {
			if (array[i] > max) {
				max = array[i];
			}
		}

		return max;
	}

	/**
	 * <p>
	 * Returns the maximum value in an array.
	 * </p>
	 * 
	 * @param array
	 *            an array, must not be null or empty
	 * @return the minimum value in the array
	 * @throws IllegalArgumentException
	 *             if <code>array</code> is <code>null</code>
	 * @throws IllegalArgumentException
	 *             if <code>array</code> is empty
	 */
	public static byte max(final byte[] array) {
		// Validates input
		validateArray(array);

		// Finds and returns max
		byte max = array[0];
		for (int i = 1; i < array.length; i++) {
			if (array[i] > max) {
				max = array[i];
			}
		}

		return max;
	}

	/**
	 * <p>
	 * Returns the maximum value in an array.
	 * </p>
	 * 
	 * @param array
	 *            an array, must not be null or empty
	 * @return the minimum value in the array
	 * @throws IllegalArgumentException
	 *             if <code>array</code> is <code>null</code>
	 * @throws IllegalArgumentException
	 *             if <code>array</code> is empty
	 * @see IEEE754rUtils#max(double[]) IEEE754rUtils for a version of this
	 *      method that handles NaN differently
	 */
	public static double max(final double[] array) {
		// Validates input
		validateArray(array);

		// Finds and returns max
		double max = array[0];
		for (int j = 1; j < array.length; j++) {
			if (Double.isNaN(array[j])) {
				return Double.NaN;
			}
			if (array[j] > max) {
				max = array[j];
			}
		}

		return max;
	}

	/**
	 * <p>
	 * Returns the maximum value in an array.
	 * </p>
	 * 
	 * @param array
	 *            an array, must not be null or empty
	 * @return the minimum value in the array
	 * @throws IllegalArgumentException
	 *             if <code>array</code> is <code>null</code>
	 * @throws IllegalArgumentException
	 *             if <code>array</code> is empty
	 * @see IEEE754rUtils#max(float[]) IEEE754rUtils for a version of this
	 *      method that handles NaN differently
	 */
	public static float max(final float[] array) {
		// Validates input
		validateArray(array);

		// Finds and returns max
		float max = array[0];
		for (int j = 1; j < array.length; j++) {
			if (Float.isNaN(array[j])) {
				return Float.NaN;
			}
			if (array[j] > max) {
				max = array[j];
			}
		}

		return max;
	}

	/**
	 * Checks if the specified array is neither null nor empty.
	 * 
	 * @param array
	 *            the array to check
	 * @throws IllegalArgumentException
	 *             if {@code array} is either {@code null} or empty
	 */
	private static void validateArray(final Object array) {
		if (array == null) {
			throw new IllegalArgumentException("The Array must not be null");
		} else if (Array.getLength(array) == 0) {
			throw new IllegalArgumentException("Array cannot be empty.");
		}
	}

	// 3 param min
	// -----------------------------------------------------------------------
	/**
	 * <p>
	 * Gets the minimum of three <code>long</code> values.
	 * </p>
	 * 
	 * @param a
	 *            value 1
	 * @param b
	 *            value 2
	 * @param c
	 *            value 3
	 * @return the smallest of the values
	 */
	public static long min(long a, final long b, final long c) {
		if (b < a) {
			a = b;
		}
		if (c < a) {
			a = c;
		}
		return a;
	}

	/**
	 * <p>
	 * Gets the minimum of three <code>int</code> values.
	 * </p>
	 * 
	 * @param a
	 *            value 1
	 * @param b
	 *            value 2
	 * @param c
	 *            value 3
	 * @return the smallest of the values
	 */
	public static int min(int a, final int b, final int c) {
		if (b < a) {
			a = b;
		}
		if (c < a) {
			a = c;
		}
		return a;
	}

	/**
	 * <p>
	 * Gets the minimum of three <code>short</code> values.
	 * </p>
	 * 
	 * @param a
	 *            value 1
	 * @param b
	 *            value 2
	 * @param c
	 *            value 3
	 * @return the smallest of the values
	 */
	public static short min(short a, final short b, final short c) {
		if (b < a) {
			a = b;
		}
		if (c < a) {
			a = c;
		}
		return a;
	}

	/**
	 * <p>
	 * Gets the minimum of three <code>byte</code> values.
	 * </p>
	 * 
	 * @param a
	 *            value 1
	 * @param b
	 *            value 2
	 * @param c
	 *            value 3
	 * @return the smallest of the values
	 */
	public static byte min(byte a, final byte b, final byte c) {
		if (b < a) {
			a = b;
		}
		if (c < a) {
			a = c;
		}
		return a;
	}

	/**
	 * <p>
	 * Gets the minimum of three <code>double</code> values.
	 * </p>
	 * 
	 * <p>
	 * If any value is <code>NaN</code>, <code>NaN</code> is returned. Infinity
	 * is handled.
	 * </p>
	 * 
	 * @param a
	 *            value 1
	 * @param b
	 *            value 2
	 * @param c
	 *            value 3
	 * @return the smallest of the values
	 * @see IEEE754rUtils#min(double, double, double) for a version of this
	 *      method that handles NaN differently
	 */
	public static double min(final double a, final double b, final double c) {
		return Math.min(Math.min(a, b), c);
	}

	/**
	 * <p>
	 * Gets the minimum of three <code>float</code> values.
	 * </p>
	 * 
	 * <p>
	 * If any value is <code>NaN</code>, <code>NaN</code> is returned. Infinity
	 * is handled.
	 * </p>
	 * 
	 * @param a
	 *            value 1
	 * @param b
	 *            value 2
	 * @param c
	 *            value 3
	 * @return the smallest of the values
	 * @see IEEE754rUtils#min(float, float, float) for a version of this method
	 *      that handles NaN differently
	 */
	public static float min(final float a, final float b, final float c) {
		return Math.min(Math.min(a, b), c);
	}

	// 3 param max
	// -----------------------------------------------------------------------
	/**
	 * <p>
	 * Gets the maximum of three <code>long</code> values.
	 * </p>
	 * 
	 * @param a
	 *            value 1
	 * @param b
	 *            value 2
	 * @param c
	 *            value 3
	 * @return the largest of the values
	 */
	public static long max(long a, final long b, final long c) {
		if (b > a) {
			a = b;
		}
		if (c > a) {
			a = c;
		}
		return a;
	}

	/**
	 * <p>
	 * Gets the maximum of three <code>int</code> values.
	 * </p>
	 * 
	 * @param a
	 *            value 1
	 * @param b
	 *            value 2
	 * @param c
	 *            value 3
	 * @return the largest of the values
	 */
	public static int max(int a, final int b, final int c) {
		if (b > a) {
			a = b;
		}
		if (c > a) {
			a = c;
		}
		return a;
	}

	/**
	 * <p>
	 * Gets the maximum of three <code>short</code> values.
	 * </p>
	 * 
	 * @param a
	 *            value 1
	 * @param b
	 *            value 2
	 * @param c
	 *            value 3
	 * @return the largest of the values
	 */
	public static short max(short a, final short b, final short c) {
		if (b > a) {
			a = b;
		}
		if (c > a) {
			a = c;
		}
		return a;
	}

	/**
	 * <p>
	 * Gets the maximum of three <code>byte</code> values.
	 * </p>
	 * 
	 * @param a
	 *            value 1
	 * @param b
	 *            value 2
	 * @param c
	 *            value 3
	 * @return the largest of the values
	 */
	public static byte max(byte a, final byte b, final byte c) {
		if (b > a) {
			a = b;
		}
		if (c > a) {
			a = c;
		}
		return a;
	}

	/**
	 * <p>
	 * Gets the maximum of three <code>double</code> values.
	 * </p>
	 * 
	 * <p>
	 * If any value is <code>NaN</code>, <code>NaN</code> is returned. Infinity
	 * is handled.
	 * </p>
	 * 
	 * @param a
	 *            value 1
	 * @param b
	 *            value 2
	 * @param c
	 *            value 3
	 * @return the largest of the values
	 * @see IEEE754rUtils#max(double, double, double) for a version of this
	 *      method that handles NaN differently
	 */
	public static double max(final double a, final double b, final double c) {
		return Math.max(Math.max(a, b), c);
	}

	/**
	 * <p>
	 * Gets the maximum of three <code>float</code> values.
	 * </p>
	 * 
	 * <p>
	 * If any value is <code>NaN</code>, <code>NaN</code> is returned. Infinity
	 * is handled.
	 * </p>
	 * 
	 * @param a
	 *            value 1
	 * @param b
	 *            value 2
	 * @param c
	 *            value 3
	 * @return the largest of the values
	 * @see IEEE754rUtils#max(float, float, float) for a version of this method
	 *      that handles NaN differently
	 */
	public static float max(final float a, final float b, final float c) {
		return Math.max(Math.max(a, b), c);
	}

	// -----------------------------------------------------------------------
	/**
	 * <p>
	 * Checks whether the <code>String</code> contains only digit characters.
	 * </p>
	 * 
	 * <p>
	 * <code>Null</code> and empty String will return <code>false</code>.
	 * </p>
	 * 
	 * @param str
	 *            the <code>String</code> to check
	 * @return <code>true</code> if str contains only Unicode numeric
	 */
	public static boolean isDigits(final String str) {
		if (StringUtils.isEmpty(str)) {
			return false;
		}
		for (int i = 0; i < str.length(); i++) {
			if (!Character.isDigit(str.charAt(i))) {
				return false;
			}
		}
		return true;
	}

	/**
	 * <p>
	 * Checks whether the String a valid Java number.
	 * </p>
	 * 
	 * <p>
	 * Valid numbers include hexadecimal marked with the <code>0x</code>
	 * qualifier, scientific notation and numbers marked with a type qualifier
	 * (e.g. 123L).
	 * </p>
	 * 
	 * <p>
	 * <code>Null</code> and empty String will return <code>false</code>.
	 * </p>
	 * 
	 * @param str
	 *            the <code>String</code> to check
	 * @return <code>true</code> if the string is a correctly formatted number
	 * @since 3.3 the code supports hex {@code 0Xhhh} and octal {@code 0ddd}
	 *        validation
	 */
	public static boolean isNumber(final String str) {
		if (StringUtils.isEmpty(str)) {
			return false;
		}
		final char[] chars = str.toCharArray();
		int sz = chars.length;
		boolean hasExp = false;
		boolean hasDecPoint = false;
		boolean allowSigns = false;
		boolean foundDigit = false;
		// deal with any possible sign up front
		final int start = (chars[0] == '-') ? 1 : 0;
		if (sz > start + 1 && chars[start] == '0') { // leading 0
			if ((chars[start + 1] == 'x') || (chars[start + 1] == 'X')) { // leading
																			// 0x/0X
				int i = start + 2;
				if (i == sz) {
					return false; // str == "0x"
				}
				// checking hex (it can't be anything else)
				for (; i < chars.length; i++) {
					if ((chars[i] < '0' || chars[i] > '9')
							&& (chars[i] < 'a' || chars[i] > 'f')
							&& (chars[i] < 'A' || chars[i] > 'F')) {
						return false;
					}
				}
				return true;
			} else if (Character.isDigit(chars[start + 1])) {
				// leading 0, but not hex, must be octal
				int i = start + 1;
				for (; i < chars.length; i++) {
					if (chars[i] < '0' || chars[i] > '7') {
						return false;
					}
				}
				return true;
			}
		}
		sz--; // don't want to loop to the last char, check it afterwords
				// for type qualifiers
		int i = start;
		// loop to the next to last char or to the last char if we need another
		// digit to
		// make a valid number (e.g. chars[0..5] = "1234E")
		while (i < sz || (i < sz + 1 && allowSigns && !foundDigit)) {
			if (chars[i] >= '0' && chars[i] <= '9') {
				foundDigit = true;
				allowSigns = false;

			} else if (chars[i] == '.') {
				if (hasDecPoint || hasExp) {
					// two decimal points or dec in exponent
					return false;
				}
				hasDecPoint = true;
			} else if (chars[i] == 'e' || chars[i] == 'E') {
				// we've already taken care of hex.
				if (hasExp) {
					// two E's
					return false;
				}
				if (!foundDigit) {
					return false;
				}
				hasExp = true;
				allowSigns = true;
			} else if (chars[i] == '+' || chars[i] == '-') {
				if (!allowSigns) {
					return false;
				}
				allowSigns = false;
				foundDigit = false; // we need a digit after the E
			} else {
				return false;
			}
			i++;
		}
		if (i < chars.length) {
			if (chars[i] >= '0' && chars[i] <= '9') {
				// no type qualifier, OK
				return true;
			}
			if (chars[i] == 'e' || chars[i] == 'E') {
				// can't have an E at the last byte
				return false;
			}
			if (chars[i] == '.') {
				if (hasDecPoint || hasExp) {
					// two decimal points or dec in exponent
					return false;
				}
				// single trailing decimal point after non-exponent is ok
				return foundDigit;
			}
			if (!allowSigns
					&& (chars[i] == 'd' || chars[i] == 'D' || chars[i] == 'f' || chars[i] == 'F')) {
				return foundDigit;
			}
			if (chars[i] == 'l' || chars[i] == 'L') {
				// not allowing L with an exponent or decimal point
				return foundDigit && !hasExp && !hasDecPoint;
			}
			// last character is illegal
			return false;
		}
		// allowSigns is true iff the val ends in 'E'
		// found digit it to make sure weird stuff like '.' and '1E-' doesn't
		// pass
		return !allowSigns && foundDigit;
	}

}
